Air bag

ABSTRACT

An air bag to be mounted in a cargo container for facilitating discharge of powder granular material from a liner filled with the powder granular material, the air bag including a synthetic resin film bag that assumes a triangle or trapezoid shape in a state where the bag has a flat form with no air injected. A gusset is formed in a base part of the triangle or in a lower base part of the trapezoid by folding the synthetic resin film inward. Flexible reinforcing covers having a triangle or trapezoid shape in accordance with the triangle or trapezoid shape of the bag are laminated respectively on one surface and the other surface of the bag. A short air outlet tube, as well as an air inlet tube, is connected to one side part of the triangle or one leg part of the trapezoid of the bag.

TECHNICAL FIELD

The present invention relates to an air bag to be mounted in a cargo container for facilitating the discharge of powder granular material (i.e., powder and/or granular material) from a liner filled with the powder granular material.

BACKGROUND ART

Patent Documents 1 and 2 below disclose an air bag to be mounted in a cargo container for facilitating the discharge of powder granular material from a liner filled with the powder granular material. This airbag includes a synthetic resin film bag that assumes a triangle or trapezoid shape in a state where the bag has a flat form with no air injected. For example, the air bag is arranged at a predetermined position in a liner that includes an outlet on its one end wall, i.e., in such a manner that the base of the triangle or the lower base of the trapezoid is adjusted to the one end wall of the liner so that the air bag extends along the inner surface of one side wall and the top surface of a bottom wall of the liner. Alternatively, the air bag is arranged at a predetermined position between the liner and a cargo container mounted with the liner, i.e., in such a manner that the base of the triangle or the lower base of the trapezoid is adjusted to the one end wall of the liner so that the air bag extends along the outer surface of the one side wall and the under surface of the bottom wall of the liner. The cargo container is inclined so that the one end wall of the liner is directed downward, and the outlet is opened to discharge approximately the whole powder granular material from the liner. Thereafter, the air bag is inflated with injected air, thereby forcing powder granular material remaining in one lower part of the one end wall of the liner toward the outlet to facilitate the discharge of the residue.

PRIOR ART DOCUMENTS Patent Documents

-   Patent Document 1: JP 2001-192089 A1 -   Patent Document 2: JP 2008-302968 A1

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

The conventional air bag as described above has the following problems: (1) When the bag is inflated, the base of the triangle or the lower base of the trapezoid is deformed into a convex arc shape toward the vertex of the triangle or the upper base of the trapezoid to form a so-called pocket space, which impedes powder granular material remaining in the one lower part of the one end wall of the liner from being forced toward the outlet in a sufficiently effective manner, resulting in a substantial amount of powder granular material remaining in the pocket space (Patent Document 1 discloses providing the air bag with an extension part to suppress the pocket space creation, which, however, leads to another problem that the extension part interferes with one or more of a plurality of the outlets formed in the liner); (2) When the bag is inflated, the bag, especially its heat-sealed portions (both side portions of the triangle or both leg portions of the trapezoid), may be broken; and (3) The air bag is non-reusable and is thrown away after a single use.

The present invention has been made in view of the aforementioned facts, and a main technical object thereof is to provide a novel and improved air bag that brings a solution to at least one of the above-described problems of the conventional air bag.

Means for Solving the Problems

As a solution to the above-described problem (1) of the conventional air bag, a first aspect of the present invention provides an air bag to be mounted in a cargo container for facilitating discharge of powder granular material from a liner filled with the powder granular material. The air bag includes a synthetic resin film bag that assumes a triangle or trapezoid shape in a state where the bag has a flat form with no air injected. A gusset is formed in a base part of the triangle or a lower base part of the trapezoid by folding the synthetic resin film inward.

As a solution to the above-described problem (2) of the conventional air bag, a second aspect of the present invention provides an air bag to be mounted in a cargo container for facilitating discharge of powder granular material from a liner filled with the powder granular material. The air bag includes a synthetic resin film bag that assumes a triangle or trapezoid shape in a state where the bag has a flat form with no air injected. Flexible reinforcing covers having a triangle or trapezoid shape in accordance with the shape of the bag are laminated respectively on one surface and the other surface of the bag.

As a solution to the above-described problem (3) of the conventional air bag, a third aspect of the present invention provides an air bag to be mounted in a cargo container for facilitating discharge of powder granular material from a liner filled with the powder granular material. The air bag includes a synthetic resin film bag that assumes a triangle or trapezoid shape in a state where the bag has a flat form with no air injected. A short air outlet tube, as well as an air inlet tube, is connected to one side part of the triangle or one leg part of the trapezoid of the bag.

It is desirable that the one surface and the other surface of the bag are welded to each other along both sides of the triangle or both legs of the trapezoid, and the reinforcing covers are bonded respectively to the one surface and the other surface of the bag along the both sides of the triangle or the both legs of the trapezoid of the bag. It is preferable that the air inlet tube and the air outlet tube are made of a synthetic resin film. It is suitable that the air bag is arranged between an inner surface of a side wall as well as a top surface of a bottom wall of the container and an outer surface of a side wall as well as an outer surface of a bottom wall of the liner that respectively face the inner surface of the side wall as well as the top surface of the bottom wall of the container, in such a manner that the base of the triangle or the lower base of the trapezoid of the bag is adjusted to one end wall of the liner on which an outlet is formed.

In the air bag according to the first aspect of the present invention, the gusset is formed in the base part of the triangle or the lower base part of the trapezoid by folding the synthetic resin film inward from both one surface side and the other surface side. Thus, an approximately flat bottom is formed at the base of the triangle or the lower base of the trapezoid when the bag is inflated. As a result, the bag is prevented from being deformed into a convex arc shape toward the vertex of the triangle or the upper base of the trapezoid to form a so-called pocket space. Therefore, powder granular material remaining in one lower part of the one end wall of the liner can be forced toward the outlet in a sufficiently effective manner.

In the air bag according to the second aspect of the present invention, the flexible reinforcing covers having a triangle or trapezoid shape in accordance with the triangle or trapezoid shape of the bag are laminated respectively on the one surface and the other surface of the bag. Thus, the bag, especially its heat-sealed portions (both the side portions of the triangle or both the leg portions of the trapezoid), is prevented as much as possible from being broken when the bag is inflated.

In the airbag according to the third aspect of the present invention, the air outlet tube, in addition to the air inlet tube, is connected to the one side part of the triangle or the one leg part of the trapezoid of the bag. Thus, injected air in the bag can be sufficiently easily exhausted through the short air outlet tube, which allows for reuse of the air bag.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 : a perspective view illustrating a typical example of a liner that is mounted in a cargo container and filled with powder granular material;

FIG. 2 : a plan view illustrating a bag according to a preferred embodiment of an air bag constructed in accordance with the present invention;

FIG. 3 : a cross-sectional view taken along line III-III of FIG. 2 ;

FIG. 4 : a simplified schematic diagram for explaining an example of a way of making the bag shown in FIGS. 2 and 3 ;

FIG. 5 : a plan view illustrating a preferred embodiment of the airbag constructed in accordance with the present invention, in which the bag shown in FIGS. 2 and 3 is provided with reinforcing covers on both surfaces thereof;

FIG. 6 : a bottom view of the air bag shown in FIG. 5 ;

FIG. 7 : a cross-sectional view taken along line VII-VII of FIG. 5 ;

FIG. 8 : a perspective view illustrating the bag of the air bag shown in FIGS. 5 to 7 that is injected with air; and

FIG. 9 : a perspective view illustrating a conventional air bag (with no gusset, no reinforcing covers, and no air outlet tube) that is injected with air.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a preferred embodiment of an air bag constructed in accordance with the present invention will be described in more detail with reference to the attached drawings.

FIG. 1 illustrates a typical example of a liner to which the airbag constructed in accordance with the present invention is applied for facilitating the discharge of powder granular material. A liner, denoted by reference numeral 2, has an elongated hollow cuboid shape with one end wall 4, another end wall 6, an upper wall 8, a bottom wall 10, and side walls 12 and 14. On the one end wall 4, a single inlet 16 and two outlets 18 a and 18 b are attached. The inlet 16 is formed by welding a base end edge of a tube to an opening formed in an upper part of the one end wall 4. The two outlets 18 a and 18 b are formed by welding a base end edge of a tube to two openings laterally spaced apart in a lower part of the one end wall 4. The liner 2 including the one end wall 4, the other end wall 6, the upper wall 8, the bottom wall 10, and the side walls 12 and 14 can be formed by appropriately processing an appropriate synthetic resin film such as a polyethylene film. The aforementioned tube can also be formed from an appropriate synthetic resin film such as a polyethylene film. At the four corners in upper end parts of the liner 2, connection cords 26 are connected via connection pieces 24 welded to the liner 2. The connection piece 24 and the connection cord 26 can also be formed from an appropriate synthetic resin such as polyethylene. This liner 2 is housed inside a cargo container (not shown) by tying the connection cords 26 provided at the four corners in the upper end parts to a lashing ring (not shown) of the cargo container. The cargo container has paired doors (not shown) located to face the one end wall 4 of the liner 2. The paired doors are usually a so-called double door that rotates about a vertical axis to open/close. The door on the user's right is first opened, and the door on the user's left is then opened. The cargo container is further provided with a bulkhead (not shown) that supports the liner 2 such that it abuts the front surface of a part of the one end wall 4 (a part other than the area of the inlet 16 and the outlets 18 a and 18 b) of the liner 2 and the under surface of the bottom wall 10 of the liner 2. The liner 2 housed inside the cargo container is filled with powder granular material through the inlet 16 in a state where the tubes forming the two outlets 18 a and 18 b are closed by, for example, tying a binding cord thereto. After the liner 2 is filled with powder granular material as required, the tube forming the inlet 16 is also closed by, for example, tying a binding cord thereto. The way of discharging powder granular material from the liner 2 will be described later.

The liner 2, the cargo container, and the bulkhead as described above themselves are well-known and do not constitute a part of the air bag constructed in accordance with the present invention; thus a detailed description thereof will be omitted in the specification.

FIGS. 2 and 3 illustrate a preferred embodiment of the air bag constructed in accordance with the present invention. An air bag, denoted by reference numeral 30, includes a synthetic resin bag 32 which can be formed from an appropriate synthetic resin film such as a polyethylene film. In a state where the bag 32 is filled with no air and has a flat form, i.e., as shown in FIG. 2 , the bag 32 has a trapezoid shape with an upper base 34, a lower base 36, and legs 38 a and 38 b. The legs 38 a and 38 b are inclined at the same angle. The form of the bag 32 is not limited to that shown in FIG. 2 , and the bag 32 may have a trapezoid shape with legs inclined at different angles or an appropriate triangle shape (e.g., an isosceles triangle shape). It is important that a gusset 40 is provided in a lower base part (i.e., a region including the lower base 36 and an area somewhat above the lower base 36) of the trapezoid. The gusset 40 is formed by folding the film inward from both one surface (top surface) side and the other surface (under surface) side. The following description is directed to a suitable way of making the bag 32 in the form as shown in FIGS. 2 and 3 . As shown in FIG. 4 , a large-diameter tube 42 made of a synthetic resin film is prepared. In one edge part of the flattened tube 42, the film is folded inward from both one surface (top surface) side and the other surface (under surface) side, thereby forming the gusset 40. Then, the tube 42 is cut along two cutting lines 44 a and 44 b, followed by welding along welding lines 46 a and 46 b, thereby making the bag 32 as shown in FIGS. 2 and 3 . As shown in FIG. 2 , it is suitable that an adhesive tape 48 is attached to both end portions of the gusset 40 in a width direction such that it lies astride both outer surfaces of the gusset 40. The adhesive tape 48 suppresses the gusset 40 from spreading when air is injected into the bag 32, thereby preventing the bag 32 from being broken in the vicinity of the legs 38 a and 38 b of the bag 32.

An air inlet tube 50 and an air outlet tube 52 are connected to the leg 38 a of the trapezoid bag 32. It is important that the air inlet tube 50 is relatively long, while the air outlet tube 52 is relatively short (the reason will be described later.) Each of the air inlet tube 50 and the air outlet tube 52, which needs to communicate with the inside of the bag 32, can be connected to the bag 32 in the following manner: A tube formed from an appropriate synthetic resin film such as a polyethylene film is cut to a required length; one end of the cut tube is located between both the surfaces of the tube 42 prior to welding along the welding line 46 a; and both the surfaces of the tube 42 are welded together along the welding line 46 a. In order to prevent the air inlet tube 50 and the air outlet tube 52 themselves from being welded and closed during the welding of both the surfaces of the tube 42, a non-welding sheet material piece (not shown) such as a paper sheet piece can be inserted into the one end of each of the air inlet tube 50 and the air outlet tube 52.

The description will continue with reference to FIGS. 5, 6 and 7 . On both surfaces of the bag 32, reinforcing covers 54 a and 54 b are laminated respectively. The reinforcing covers 54 a and 54 b may be substantially the same in shape and dimensions as the bag 32. Accordingly, in a state where the bag 32 according to the illustrated embodiment is filled with no air and has a flat form, the reinforcing covers 54 a and 54 b have a trapezoid shape with an upper base 56, a lower base 58, and legs 60 a and 60 b, and the legs 60 a and 60 b are inclined at the same angle. The reinforcing covers 54 a and 54 b, which can be formed of an appropriate flexible material, are suitably formed from a laminated synthetic resin sheet usually called a tarp, or PE cloth paper obtained by laminating a cloth (mesh) made of a synthetic resin such as high-density polyethylene on unbleached kraft paper. The reinforcing covers 54 a and 54 b can be suitably laminated on both the surfaces of the bag 32 by attaching corresponding sites of the reinforcing covers 54 a and 54 b along the welding lines 46 a and 46 b of the bag 32 with an appropriate adhesive means such as a double-stick tape. In FIGS. 5 and 6 , sites 62 of adhesion between the bag 32 and the reinforcing covers 54 a and 54 b are indicated with a plurality of dots. It is desirable that the bag 32 and the reinforcing covers 54 a and 54 b are not attached to each other at a site where the air inlet tube 50 and the air outlet tube 52 are connected, in order not to inhibit the air inlet tube 50 and the air outlet tube 52 from being inflated when air is injected or exhausted.

As shown in FIG. 6 , appropriate binding cords 64 are connected to the reinforcing cover 54 b laminated on the other surface (surface not shown in FIG. 2 ) of the bag 32 via appropriate connection pieces 63 attached to the reinforcing cover 54 b, in a central part in the width direction in the vicinity of the upper base 56, one end part (right end part in FIG. 6 ) of the upper base 56, a middle part in the width direction in the vicinity of the lower base 58, and both end parts of the lower base 58 in the width direction.

Next, a description will be given of a typical way of using the air bag 30 as described above. According to the embodiment shown in FIG. 1 , the air bag 30 is folded in half along the longitudinal center line so that the two halves form an angle of substantially 90 degrees with each other, and is interposed between a cargo container (not shown) and the liner 2 so that the halves of the air bag 30 are located to face the respective outer surfaces of the side wall 12 and the bottom wall 10 of the liner 2. The air bag 30 is arranged at a required position in the cargo container before the liner 2 is mounted in the cargo container, and the binding cords 64 attached to the reinforcing cover 54 b can be tied to a lashing ring or the like of the cargo container. As can be understood with reference to FIG. 2 , the lower base 36 of the bag 32 and the lower base 58 of the reinforcing covers 54 a and 54 b of the air bag 30 are substantially adjusted to the one end wall 4 of the liner 2.

When powder granular material is to be discharged from the liner 2, the cargo container is tilted, so that the liner 2 is inclined in such a manner that the one end wall 4 is directed downward while the other end wall 6 is directed upward. Prior to the tilting of the cargo container, one of the paired doors, i.e., the door on the user's right, of the cargo container is opened, so that the outlet 18 b of the liner 2 is exposed. Thereafter, the binding cord tied to the tube forming the outlet 18 b is untied to open the outlet 18 b, to which an appropriate outlet guide pipe (not shown) is connected. Then, powder granular material is discharged from the liner 2 through the outlet 18 b and the outlet guide pipe. Even after most powder granular material in the liner 2 has been discharged, a substantial amount of powder granular material still remains in the lower corner between the one end wall 4 and the side wall 12 of the liner, due to the fact that powder granular material is discharged through the outlet 18 b located in the lower right part of the one end wall 4 of the liner 2. In order to facilitate the discharge of such residual powder granular material, the relatively long air inlet tube 50 attached to the air bag 30 is pulled out from the cargo container, and air is injected into the bag 32 through the air inlet tube 50. As a result, the bag 32 is inflated as shown in FIG. 8 , thereby allowing powder granular material remaining in the lower corner between the one end wall 4 and the side wall 12 of the liner 2 to be forcibly removed toward the outlet 18 b and discharged through the outlet 18 b (in FIG. 8 , the reinforcing covers 54 a and 54 b are not shown for simplification.) At this time, the air outlet tube 52 is substantially closed by being compressed between both the surfaces of the bag 32 in the vicinity of the leg 38 a of the bag 32 in response to the inflation of the bag 32. Thus, there is no need to take active measures to close the air outlet tube 52 by, for example, tying a binding cord thereto.

The bag 32 of the air bag 30 constructed in accordance with the present invention includes the gusset 40 in its lower base part. Thus, as clearly shown in FIG. 8 , an approximately flat bottom is formed at the lower base 36 of the bag 32. This prevents the lower base 36 of the bag 32 from being substantially displaced inward from the one end wall 4 of the liner 2, and accordingly a so-called pocket space is not created. As a result, powder granular material remaining in the lower corner between the one end wall 4 and the side wall 12 of the liner 2 can be forcibly removed toward the outlet 18 b in a sufficiently effective manner and discharged through the outlet 18 b. In contrast, a conventional bag 32′ with no gusset as shown in FIG. 9 is deformed inward into a convex arc shape at its lower base 36′ to create a so-called pocket, in which a substantial amount of powder granular material is likely to remain.

Further, according to the air bag 30 constructed in accordance with the present invention, the reinforcing covers 54 a and 54 b are laminated on both the surfaces of the air bag 32. Thus, for example, the air bag 32 is prevented as much as possible from being broken in the vicinity of the legs 38 a and 38 b of the air bag 32 when air is injected into the air bag 32.

After powder granular material in the liner 2 has been sufficiently discharged due to the action of the air bag 30, the liner 2 is usually removed from the cargo container and discarded. Afterwards, the cargo container becomes available to a field user, who then enters the cargo container, inserts an aspiration nozzle (not shown) of an air suction machine brought in from outside the cargo container into the air bag 32 through the air outlet tube 52 of the air bag 30, and gets the air suction machine working to exhaust air from the air bag 32 (if the aspiration nozzle of the air suction machine is merely connected to the outer end of the air outlet tube 52 to exhaust air in the air bag 32, the air outlet tube 52 is closed during air aspiration, making it impossible to exhaust air.) According to the air bag 30 constructed in accordance with the present invention, the air inlet tube 50, which is used in a state where the liner 2 is mounted in the cargo container, is relatively long because it needs to be pulled out from the cargo container. On the other hand, the air outlet tube 52, which becomes available to a field user who enters the cargo container after the removal of the liner 2 from the cargo container, is relatively short. Thus, it is sufficiently easy to insert the aspiration nozzle of the air suction machine into the air bag 32 through the air outlet tube 52. After air has been exhausted from the bag 32, the airbag 30 can be used repeatedly for another liner to be mounted in a cargo container and filled with powder granular material.

In a case where the two doors of the cargo container are opened, so that powder granular material in the liner 2 is discharged not only through the outlet 18 b but also through the outlet 18 a, only a slight amount of powder granular material remains in the liner 2, and accordingly the air bag 30 is not necessarily required to be activated. Meanwhile, in a case where the liner has only one outlet at the center of the one end wall in the width direction, powder granular material tends to remain in both side parts of the liner. In such a case, two air bags 30 can be attached, one to one side of the liner and the other to the other side of the liner.

EXPLANATIONS OF LETTERS OR NUMERALS

-   -   2: liner     -   4: one end wall of liner     -   6: another end wall of liner     -   8: upper wall of liner     -   10: bottom wall of liner     -   12: side wall of liner     -   14: side wall of liner     -   16: inlet of liner     -   18 a: outlet of liner     -   18 b: outlet of liner     -   30: air bag     -   32: bag     -   34: upper base of bag     -   36: lower base of bag     -   38 a: leg of bag     -   38 b: leg of bag     -   40: gusset     -   50: air inlet tube     -   52: air outlet tube     -   54 a: reinforcing cover     -   54 b: reinforcing cover 

1. An air bag to be mounted in a cargo container for facilitating discharge of powder granular material from a liner filled with the powder granular material, the air bag including a synthetic resin film bag that assumes a triangle or trapezoid shape in a state where the bag has a flat form with no air injected, wherein a gusset is formed in a base part of the triangle or a lower base part of the trapezoid by folding the synthetic resin film inward.
 2. The air bag according to claim 1, wherein flexible reinforcing covers having a triangle or trapezoid shape in accordance with the shape of the bag are laminated respectively on one surface and the other surface of the bag.
 3. The air bag according to claim 2, wherein the one surface and the other surface of the bag are welded to each other along both sides of the triangle or both legs of the trapezoid, and the reinforcing covers are bonded respectively to the one surface and the other surface of the bag along the both sides of the triangle or the both legs of the trapezoid of the bag.
 4. The air bag according to claim 1, wherein a short air outlet tube, as well as an air inlet tube, is connected to one side part of the triangle or one leg part of the trapezoid of the bag.
 5. The air bag according to claim 4, wherein the air inlet tube and the air outlet tube are made of a synthetic resin film.
 6. An air bag to be mounted in a cargo container for facilitating discharge of powder granular material from a liner filled with the powder granular material, the air bag including a synthetic resin film bag that assumes a triangle or trapezoid shape in a state where the bag has a flat form with no air injected, wherein flexible reinforcing covers having a triangle or trapezoid shape in accordance with the shape of the bag are laminated respectively on one surface and the other surface of the bag.
 7. The air bag according to claim 6, wherein the one surface and the other surface of the bag are welded to each other along both sides of the triangle or both legs of the trapezoid, and the reinforcing covers are bonded respectively to the one surface and the other surface of the bag along the both sides of the triangle or the both legs of the trapezoid of the bag.
 8. The air bag according to claim 6 or 7, wherein a short air outlet tube, as well as an air inlet tube, is connected to one side part of the triangle or one leg part of the trapezoid of the bag.
 9. The air bag according to claim 8, wherein the air inlet tube and the air outlet tube are made of a synthetic resin film.
 10. An air bag to be mounted in a cargo container for facilitating discharge of powder granular material from a liner filled with the powder granular material, the air bag including a synthetic resin film bag that assumes a triangle or trapezoid shape in a state where the bag has a flat form with no air injected, wherein a short air outlet tube, as well as an air inlet tube, is connected to one side part of the triangle or one leg part of the trapezoid of the bag.
 11. The air bag according to claim 10, wherein the air inlet tube and the air outlet tube are made of a synthetic resin film.
 12. The air bag according to claim 1, being arranged between an inner surface of a side wall as well as a top surface of a bottom wall of the container and an outer surface of a side wall as well as an outer surface of a bottom wall of the liner that respectively face the inner surface of the side wall as well as the top surface of the bottom wall of the container, in such a manner that the base of the triangle or the lower base of the trapezoid of the bag is adjusted to one end wall of the liner on which an outlet is formed.
 13. The air bag according to claim 6, being arranged between an inner surface of a side wall as well as a top surface of a bottom wall of the container and an outer surface of a side wall as well as an outer surface of a bottom wall of the liner that respectively face the inner surface of the side wall as well as the top surface of the bottom wall of the container, in such a manner that the base of the triangle or the lower base of the trapezoid of the bag is adjusted to one end wall of the liner on which an outlet is formed.
 14. The air bag according to claim 10, being arranged between an inner surface of a side wall as well as a top surface of a bottom wall of the container and an outer surface of a side wall as well as an outer surface of a bottom wall of the liner that respectively face the inner surface of the side wall as well as the top surface of the bottom wall of the container, in such a manner that the base of the triangle or the lower base of the trapezoid of the bag is adjusted to one end wall of the liner on which an outlet is formed. 